Furnace for road planing machines



Feb. 17, 1942. o. o. DAvls FURNACE FOR ROAD PLANING MACHINES Filed Aug. 19, 1939 Patented Feb. 17, 1942 FURNACE FOR ROAD PLANING MACHINES Oscar 0. Davis, Oakland, Calif., assignor of onehalf to J. C. Compton, McMinnville, Oreg.

Application August 19, 1939, Serial No. 291,066

1 Claim.

The present invention relates to road planing machinery and particularly to a machine for leveling or reducing the irregularities in roads of asphalt or macadam composition surface.

The irregularities which develop in the surface of asphalt or macadam roads may be removed by scraping or planing away a thin layer of the surface. This planing may be done with practical efficiency only when the surface is soft or plastic as it becomes when it is subjected to heat. Machines have been used which move over the surface of the road carrying an oven or furnace to heat the surface and scarifying and scraping means which follow the oven respectively to disintegrate and smooth the surface while it is in a heated and softened condition.

The present invention contemplates a machine of this general character, in that it employs means for heating the road surface and for planing it while it remains in a heat softened condition. The machine of this invention, however, embodies certain improvements in both heating and planing means which make possible the elimination of scarifying or otherwise disintegrating the surface, and effect a superior surfacing by merely heating and planing.

It is the object of the present invention to provide a road planing machine in which a surface heating furnace and a planer blade effect a leveling of the road surface in a relatively rapid and inexpensive manner.

A further object is to provide in such a machine a furnace supported to move in very close proximity to a road surface and in a manner to confine heat particularly to that portion of the surface desired to be heated, and so supported that 'it will ride freely without possibility of damage over high parts in the r'oad or other obstacles.

A still further object is to provide a planing blade and support therefor in a relationship to said furnace which will enable a complete surfacing treatment of the heated road to be made by a single cutting operation.

One form of the present invention is illustrated in the accompanying drawing, and further objects and advantages of the invention are made apparent in the following specification, in which reference is made to the drawing. The specification should be read with the understanding that while the machine is referred to as a road surfacing machine, it is designed for operation on any large, relatively atsurface covered with a heat softenable pavement of any kind similar to those kinds generally referred to as macadam or asphalt.

In the drawing- Fig. 1 is a side elevation of a road planing machine embodying the present invention;

Fig. 2 is a vertical longitudinal section of the furnace which forms a part of the machine illustrated in Fig. 1; and

Fig. 3 is a sectional view taken through the planing blade assembly.

The invention as illustrated in the accompanying drawing is combined with .a road working machine ofV conventional construction, wellknown to the trade. In general, this machine comprises a motor enclosed beneath a hood I0 and supported on a pair of frame members II to drive two pairs of road wheels I2. The frame members II extend forwardly to form an arch I3 and are supported at their forward ends by a pair of road wheels I4 coupled by conventional mechanism for steering by the usual steering wheel I5. The space beneath the arch I3, which is intended for various types of road working tools or blades, is in the present invention occupied by a furnace I6 and planer blade assembly generally indicated at I 1. The furnace I6 is generally rectangular in shape, diminishing slightly toward its forward end, and is made preferably of heavy-gauge sheet metal with suitably reinforced corners. The interior of the furnace is lined with a plastic composition of reproof material I8. The furnace is supported by a pair of pivoted arms I9 which swing from their forward ends on a pin 20 carried transversely of the forward end of the main frame of the machine. The rear ends of the arms I9 are pivoted to the furnace through the medium of plates 2I carried by angular members 22 secured to the top of the furnace. Adjusting links 23 are connected by bolts 24 extending through slots 25 in the angles 22, and are also pivotally connected to the arms I9 by bolts 26. These links are adjustable by loosening the bolts 24 and 26 so that the bolt. 24 will slide in the slot 25 to adjust the furnace for its normal operating position with its forward end slightly closer to the road surface than its rear end. Supported in this manner, the entire furnace is fre'e to swing about the pin 20. Its downward swinging position is limited by a flexible connection such as the chain 21, the upper end of which is connected to an arm 28 adapted to be raised and lowered by gears encased within a gear housing 29 and operated through a power transmission not shown, by

means of which said gears are connected with the main motor of the machine. f

By raising or lowering the arm 28, the furnac may be raised or lowered toward the road surface to accommodate the particular conditions under which the machine is operating. In normal operation, the forward end of the furnace lies very close to the surface of the road, and a pair of runners 38, fixed to the forward opposite edges of the furnace, are adapted to engage with the road if the furnace strikes irregularities or obstacles of any sort on the surface of the road. Due to the manner in which the furnace is supported, it is free to swing upwardly when the runners at its forward end strike an obstacle, and it will ride freely over any such obstacle without damage to any part of the machine and without interruption of the work being done. This makes practical the positioning of the forward end of the furnace considerably closer to the road surface than would otherwise be safe, and as a result of this close positioning and the diminishing size of the furnace toward its forward end, heat which is introduced into the furnace at its rear end is concentrated against the surface of the road.

A plurality of oil burners 3| are supported by a manifold 32 at the rear of the furnace and in registry with openings 33 in the rear furnace wall. Oil is delivered to these burners through a flexible conduit 34, and air under pressure to support combustion of this oil is delivered through a flexible conduit 35. The conduit 34, as illustrated in Fig. l, communicates with an oil pump 36 which draws oil from a tank 31 and pumps it to the burners. The conduit 35 leads to an air blower 38 for directing air to the burners. Both the pump 36 and blower 38 take power from the main motor through conventional mechanism. Because of the pivotal support of the furnace being positioned forward of the foremost end thereof, any swinging movement caused by the furnace riding over an obstacle in the road will cause the rear end of the furnace to rise slightly and the burners which are supported by brackets 31 on the furnace will rise with it without danger of being damaged and without interruption of operation. An extension 39 of the main burner control valve places the burners conveniently under control of the operator.

As the machine is driven over a macadam or asphalt road surface at a speed of, say, 30 feet per minute, the heat applied to the surface by the furnace supported in this manner is sufficient to soften the surface so that it may be planed smooth by a blade which travels directly behind the furnace. The planer blade assembly, which is provided for this purpose, is supported by a pair of arms 40 carried by a ring 4I, which is rotatably mounted with respect to a subframe 42. This subframe 42 is pivoted at the forward end of the main frame of the machine and may be raised and lowered by a power jack 43. The ring 4| may be rotated by conventional means not shown to adjust the angle of the planer blade with respect to the direction of travel of the machine. The blade, as best illustrated in Fig. 3, is carried by a block 44 pivoted as at 45 to the arms 40 and adjustable about said pivot through the medium of slotted links 46 and bolts 41. The cutting edge of the planer blade is preferably in the form of a hardened steel plate 48 clamped to the forward face of the block 44 by a plate 49 and bolts 50. Adjusting screws 5I are arranged to engage the upper edge of the plate` 48 to adjust the distance that it projects toward the road surface below the edge of the block 44. The planer blade is, by the mechanism described, adjustable vertically and angularly, and when properly adjusted and used in conjunction with the furnace supported as herein disclosed, will act to plane the surface of a macadam or asphalt road to a perfectly smooth or level condition without the necessity of first scarifying or otherwise disturbing the surface after it has been heated to a workable consistency.

While the present invention has been more or less specifically described and illustrated, I wish it understood that vvarious changes may be resorted to within 'the scope of the appended claim.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

In a machine of the character described, a frame, a furnace for heating a road surface comprising a housing with an open bottom positioned adjacent the surface of the road, arms rigidly secured to the housing and extending forwardly thereof and pivoted relative to the frame at a point forward of the housing, means for adjusting the rigid connection between the arms and the housing to vary the normal angle between, the road surface and the housing, and means for raising and lowering the furnace about said pivotal support.

OSCAR O. DAVIS. 

